The Decision Tree: How Smarter Choices Lead to Better Health

Health is really just a system of inputs and outputs, which means we have more control over it than we might have thought.
Photo: Jens Mortensen

Life is complicated — especially when it comes to our health. Once we reach a certain age, we start to realize that health is a variable, not a constant. Our knees ache, our pace slows, and we’re diagnosed with diabetes or even cancer. And because the stakes are so high and the options so dizzying, we may stop engaging with our health altogether. We let doctors and insurance companies decide on our care, and we focus our energies on what we can control — our bank accounts, our relationships, but not, alas, our health.

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That’s too bad, because health is really just a system of inputs and outputs. The inputs include the choices we make: what we eat, whether we exercise, how much we sleep, whether we heed our doctors’ orders. These decisions combine with other inputs, things that we may not even consider information and that we probably know much more about than our doctors, like our family history, where we live, our jobs, our stress levels, and so on. All of these inputs create one primary output unique to us alone: our health, for good or ill.

This means we have more control over our health than we might have thought. By monitoring and tweaking our inputs, we can influence and even determine our well-being. Taken all at once, our health may seem inscrutable; laid out in a sequence, it becomes a series of decisions, each with risks, benefits, and trade-offs. In other words, we can organize our health options into a decision tree, a method for factoring in our inputs, mapping out our options, and guiding us along the best possible path.

A decision tree is a simple idea — many of us learned to draw them (in the form of flowcharts) in elementary school. And decision trees are already all around us. They’re common in engineering and industry, where they’re known as algorithms. The pharmaceutical industry uses them to plan safe clinical trials. Financial-service quants use them to root out credit card fraud. They’re even used by city planners to design street patterns and map bus routes. In these cases, decision trees can be complicated tools, laden with mathematics and computer science.

The Four Components of a Decision Tree

Illustration: Borja Bonaque

But they needn’t be only for the experts. In an age of too much information and too little illumination, a decision tree can be a tool that nudges any of us to think through our options and to act consciously and with consideration. A decision tree can be as straightforward as a list of the pros and cons of a particular option that we complete before we act. It can be a simple and useful way to turn the health data we already have into a system for better choices and better outcomes.

And auspiciously, we’re at a moment when more data than ever lies within ready reach. Whether it’s personal genomics services like 23andMe or screening tests or self-tracking iPhone apps, each of us can draw on a wealth of personalized data sources that turn generic medical advice into customized health equations. And this is always-on data: Instead of checking in on our health episodically — when we visit the doctor or get lab test results — we can now tap into a constant stream of information and opportunity. We can minimize our uncertainty and maximize our control. We can build ever more sophisticated, and useful, decision trees.

In the following pages, you’ll meet three individuals, each facing a different medical quandary. As their experiences show, the right decision tree can bear the fruit of a better life.

Should Teri Smieja have preemptive surgery to protect against breast and ovarian cancers?

Teri Smieja
Portrait: Alexandra Compain-Tissier

Teri Smieja had a choice to make. A mother of two living in the small town of Ridgecrest, California, she learned in February 2009 that she has a much higher risk of developing breast and ovarian cancers than the typical American woman. And she needed to figure out what to do about it.

It had happened very fast. In late 2008, her aunt went on a trip to Israel. When she came back to the States, she explained to Smieja that Ashkenazi Jews like themselves were more likely to have mutations in two genes known as BRCA1 and BRCA2. Those mutations put women at a much higher risk for breast and ovarian cancers. Sixty percent of women who have mutations in one or both of the genes will develop breast cancer, and up to 40 percent will develop ovarian cancer. (The average American female has about a 12 percent risk of breast cancer, and a 1.4 percent chance of ovarian cancer.) For Smieja, who didn’t really identify as Jewish, this was all new. “I had never heard of Ashkenazi anything before,” she says, let alone BRCA genes. But she did know that ovarian cancer ran in her family — her grandmother had it, her aunt had it, her mother has it. “I always figured I had a higher chance of getting cancer,” she says, but she hadn’t known there was a way to measure that risk.

So Smieja took a genetic test and learned that she was positive for the BRCA1 mutation. That finding, combined with her family history, made it more than a possibility that she would develop breast or ovarian cancer — it became a likelihood. In a term that reflects the age we live in, women like Smieja are known as previvors — they don’t have a cancer yet, but they surely have something. The question now was what to do next. “I had this paper in my hand that said I have up to an 87 percent risk of getting cancer by age 70. And, of course, I started crying; I was really upset. But then it hit me: It didn’t say I had cancer; it said I could get cancer. So I said, ‘Stop feeling sorry for yourself. This is good news. I can do something about this.'”

Teri’s Decision Tree

Teri Smieja had to determine whether the trauma of invasive surgery was outweighed by the reduced risk of breast and ovarian cancers.

Graph: Borja Bonaque

Slowly, her decision tree began to emerge. Estrogen promotes cell division in women and therefore spurs the proliferation of cancer cells. Since the ovaries produce most of the estrogen in the female body, it’s often recommended that women with an increased risk have their ovaries and uteruses removed. An oophorectomy and hysterectomy, then, not only brings the risk of ovarian cancer close to zero but also reduces the breast-cancer risk by about 50 percent. After spending a lot of time on the Internet and visiting a genetic counselor (“They said I did it wrong. I was supposed to go to the counselor first,” she recalls), Smieja decided to have the oophorectomy and hysterectomy.

As far as surgeries go, oophorectomy with hysterectomy is relatively straightforward and can be performed laparoscopically in just a few hours. One downside was that she wouldn’t be able to have any more children, but Smieja wasn’t planning to anyway.

The next choice facing her was whether to have a preemptive double mastectomy (also known as a bilateral prophylactic mastectomy). This one was more difficult. Some women with high risk opt for this procedure because estrogen receptors in the breasts make them susceptible to cancer. But it is a more traumatic procedure, both in terms of recovering from the wounds and for social and psychological reasons. (For Smieja, it meant she could no longer breast-feed her second child.) And while it would further reduce the risk of breast cancer — by about 90 percent — the benefits were not as pronounced as with the oophorectomy.

For Smieja, the decision was traumatic to navigate. But ultimately it came down to her desire to reduce her risk through all available means. That meant waiting a few months to wean her baby, then having the procedures. “I’m done with that decision,” she says. “This is what I need to do. I need to be around for my kids. I am not my ovaries. I am not my breasts.”

Should Frank Kozik give up smoking, or does the pleasure of lighting up outweigh the consequences?

Frank Kozik
Portrait: Alexandra Compain-Tissier

Frank Kozik knows how hard it is to quit smoking. He smoked for 39 years, off and on — and he’s just 48 years old. You read that right: Kozik, a renowned poster designer since the heyday of alternative rock, has been smoking since he was 8 years old.

Like so many smokers, Kozik has quit several times. When he began bicycling in the 1980s, he kicked the habit for five years — until he started seeing a woman who smoked. A few years later, when he started dating a more health-conscious woman, he quit again — only to resume after they broke up about a year later. Kozik has always been well aware of the risks — but he also knows the benefits. “Smoking is a really pleasurable thing,” he says. “It’s like a little high every time you light up. Of course, with every cigarette I also thought, ‘Is this the one that’s going to give me cancer?’ But that was an abstract thought, and that little high was so much more real.”

Kozik’s description is spot-on. Of all our bad health habits, smoking is one of the worst of all possible worlds: It’s among the least healthy and the hardest to stop. Half of all lifelong smokers will die of a smoking-related illness; nearly a third of all cancer deaths are caused by smoking. Very few health behaviors are so strongly associated with such lethal results. So what keeps smokers puffing away? Neurologically, smoking activates the mesocorticolimbic dopamine system in the brain, which drives the reward circuit, the motivational circuit, and the learning/memory circuit. (This means that smoking is a learned behavior, self-rewarding, and motivational all at the same time!) Each individual node in the smoker’s decision tree pits an immediate tangible benefit against a longer-term abstract one.

This tension exemplifies the paradox of behavior change: We know what we are supposed to do, but we find all sorts of reasons not to do it. As a result, more than 85 percent of Americans don’t eat enough fruits and vegetables, two-thirds are overweight — and 20 percent continue to smoke cigarettes. We don’t lack for information. We lack for incentives.

For Kozik, those incentives finally started to register when he hit his mid-forties and he began to feel the effects of so many years of smoking. “All these health issues began to pop up,” he says, and in early 2008, when he found it “harder to carry stuff up the stairs,” he started to cut back from his two-pack-a-day habit to about 15 cigarettes a day.

But last year, Kozik faced a starker trade-off than a little shortness of breath. His dentist told him that smoking had severely aggravated his gums. If he didn’t quit smoking, he was likely to start losing his teeth. “Right there, it became something real,” Kozik says. “What do I value more: my teeth or smoking cigarettes? I mean, cancer was always this vague thing; you can’t see your lungs. But you can see your teeth. It was a pretty clear decision.” Kozik quit cold turkey last October and is resolved to never light up again.

“My entire life has been motivated by the possibility of what comes next,” Kozik explains. “I’m a selfish person — we all are — and every decision I make comes down to which choice will benefit me more. But most of these choices are totally abstract, toward some idealized goal. Every once in a while, though, you’ll hit a choice that’s real. Having your teeth fall out is real. At that point, the value of a mild narcotic stimulant is zero.”

Frank’s Decision Tree

Frank Kozik knew smoking could kill him but found the habit too pleasurable to quit for good, even though he had quit temporarily several times. Then a potentially immediate and drastic consequence caused him to reconsider his choices.

Graph: Borja Bonaque

Alexandra Carmichael has chronic pain. What’s causing it, and how should she treat it?

Alexandra Carmichael
Portrait: Alexandra Compain-Tissier

There are roughly 50 million Americans living with chronic pain, and for them, the hardest thing may be identifying the true cause of their problem. Scans and blood tests often only leave people in the dark and in distress. Pain sufferers may want to build a decision tree, but discovering what the true inputs are can be a lengthy and frustrating process.

At 20 years old, all Alexandra Carmichael knew was that she was in pain. Constant, steady pain — burning, stabbing, soreness — in her pelvis and genitals. For the next 10 years, she bounced among gynecologists who told her not to worry and specialists who couldn’t specify anything. She endured endless tests, including an ultrasound to rule out polycystic ovary syndrome and blood panels to rule out hypothyroidism, adrenal fatigue, and a high testosterone level. Time after time, the tests revealed nothing abnormal or conclusive. As a diagnosis eluded her, she got married and had two children. “I just wanted some ideas, some clue, some information. But there wasn’t any that I could find,” she says.

Finally, in 2006, a new doctor gave her an accurate diagnosis: vulvodynia, a condition characterized by persistent pain in a woman’s pelvis and genitals. It can be intermittent or constant, and it makes many aspects of day-to-day life, including sex, seem almost impossible. Despite the fact that about 16 percent of women will suffer from it during their lives, it is a woefully understudied condition. “It was a huge validation that it was not all in my head, that there was actually a name for what I had and that other women had had it,” Carmichael recalls. “It freed me up to focus on how to treat my body rather than try to figure out what I had.”

But her ordeal wasn’t over. She’d spend another two years sorting through various treatments, each one a Hobson’s choice between trying something or trying nothing. After a battery of other tests — cholesterol, thyroid, blood panels — she discovered that her estrogen levels were low. Eventually, she and her doctor came up with the right level of hormone replacement therapy to allow her to live “95 percent pain free.”

Carmichael’s experience led her to cofound CureTogether, an online health community where people can share their experience with more than 400 conditions and compare their symptoms, treatments, and results. The information is robust enough that the site has actually advanced research into vulvodynia and several other conditions. “It took me 10 years to find out what I had, and it took two years to find the right treatment,” she says. “That simply wouldn’t be the case anymore. It would not take anywhere near that long for somebody who finds CureTogether. Now there are other women like me, sharing ideas and data. It shortens the decision tree considerably.”

Alexandra’s Decision Tree

Alexandra Carmichael spent a decade looking for a diagnosis. It took her another two years to determine the best treatment options.

Graph: Borja Bonaque

Wired executive editor Thomas Goetz (thomas@wired.com) is the author of The Decision Tree: Taking Control of Your Health in the New Era of Personalized Medicine, to be published this month by Rodale.

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